1. Field of the Invention
The present invention relates in general to mechanical valve systems and in particular to a sequencing valve mechanism for controlling the application of pressure from a pulsating source of pressure to a pair of output appliances.
2. Description of the Prior Art
In a pneumatic or hydraulic control system, pressure is supplied from a source to operate one or more output appliances. Generally, it is desirable to regulate the application of such pressure according to a predetermined sequence. A common mechanism for regulating a pneumatic control system utilizes a valve actuating means which is responsive to the application of pressure thereto. For example, U.S. Pat. No. 3,134,304 to Hager discloses a pressure operated pump utilizing a lever acutated by a compressor or pump shaft to work a spring to an over-center position, whereupon spring forces throw the lever completely over to operate a movable valve which is adapted to be controlled by the lever. U.S. Pat. No. 3,955,431 to Davis et al. discloses a valve actuator toggle mechanism for opening and closing a rotary valve by pushing a push rod.
Other mechanisms employ cam or stop means to regulate the operation of a pneumatic control means. U.S. Pat. No. 3,078,500 to Millard et al. discloses an automatic door closer and check mechanism including a generally triangularly-shaped cam opening for guiding a cam plate to define the opening and closing motions. U.S. Pat. No. 3,334,521 to Kast discloses a control mechanism which allows an actuator to move a load from one of a plurality of pre-selected stop positions to another such stop position, yet prevents the load forces acting upon the mechanism from actuating the mechanism away from a pre-selected stop position.